Under increasing pressure to contain medical costs, physicians find themselves wondering whether it is ever proper to ration health care at the bedside.Opinion about this is divided, but one thing is clear: Whether physicians should ration at the bedside or not, they ought to be able to recognize when they are doing so. This paper describes three conditions that must be met for a physician's action to qualify as bedside rationing. The physician must 1) withhold, withdraw, or fail to recommend a service that, in the physician's best clinical judgment, is in the patient's best medical interests; 2) act primarily to promote the financial interests of someone other than the patient [including an organization, society at large, and the physician himself or herself]; and 3) have control over the use of the beneficial service. This paper presents a series of cases that illustrate and elaborate on the importance of these three conditions. Physicians can use these conditions to identify instances of bedside rationing; leaders of the medical profession, ethicists, and policymakers can use them as a starting point for discussions about when, if ever, physicians should ration at the bedside.